"Firstly, for those people that may have witnessed Catherine and her red Ford Focus arriving at the scene which is alongside the A358 near Ilminster. Did anybody see that car arrive? Did anybody see suspicious people arrive or leave the scene at about 6am to 6.30am on a busy road? We need you to call us. The second part of the appeal is to help us understand Catherine's private and social life."

The post-mortem has yet to take place and detectives are not able confirm whether Catherine died before or after the fire, he added.

Catherine was a member of dating website speeddate.com with the user name cafx101 – after her nickname "Caf" – and said she was looking for 'dating and friendship'.

She described herself as "single" and described her 5ft 3in frame as "athletic" and "toned", stating that she had blue eyes and brown hair.

The fun-loving graduate admitted she had an ex from her past that she considered to be the "one that got away" but said she would not consider contacting them again.

On August 25, Catherine updated the cover photo on her Facebook profile with a picture of a woman covering her face with a book.

Accompanying the picture was the cryptic message: "You can't start the next chapter of your life if you keep re-reading the last one."

Tributes were paid to the young woman who lived in the town of Chard with her family, and achieved a first-class degree in business management.

Maurice Hicks, head teacher of Holyrood Academy in Chard where she was a former pupil, spoke of his shock at the news.

"Everyone at Holyrood Academy is deeply saddened and shocked to hear the news about Catherine," he said. "She is warmly remembered as a very friendly young person, gregarious and with a great sense of humour."